The invention relates to improvements in transmissions for use in the power trains of motor vehicles, and more particularly to improvements in so-called hybrid or composite transmissions which can be shifted into selected gears automatically as well as manually.
Published German patent application Serial No. 37 17 675 discloses a transmission wherein a gear assembly is shiftable into and between a plurality of gears (including reverse, neutral and forward gears) by a shifting means including a gate defining first and second gear selecting paths and a gear selector which is movable along the first path between a plurality of positions including first, second and third positions in which the assembly is respectively in reverse, neutral and forward gears. The gear selector is movable between the aforementioned third position and the second path and manually between different positions along the second path. The gear shifting means further comprises a signal receiving, processing and transmitting control unit, at least one actuator which is responsive to signals from the control unit and is arranged to move the shifting device to a selected one of the plurality of gears as a function of the characteristics of signals being transmitted by the control unit, and at least one sensor which is set up to monitor the positions of the selector in the first and/or second path and to transmit corresponding signals to the control unit.
An advantage of the above outlined transmission is that, when the selector (such as a lever) is to shift the transmission into reverse, neutral or forward gear, such manipulation of the shifting device can be effected by the at least one actuator automatically in response to signals which are being transmitted to the control unit by the at least one sensor. When the gear assembly has been shifted into a forward gear, the lever can be moved into the second path for manual advancement to a selected position in the second path.
Transmissions embodying the above outlined gear assemblies and the combined automatic and mechanical shifting means therefor enjoy an increasing popularity.
The disclosure of the published German patent application Serial No. 37 17 675 is incorporated herein by reference.